Underpinning of buildings



Feb. 19, 1952 F. PRYKE 2,586,712

UNDERPINNING OF BUILDINGS Filed Aug. 5, 1947 2 $HEETSSHEET l Inventor FORDHAH PRYKE 0/ QX M 14.2660

Aitorney Feb. 19, 1952 F. PRYKE' 2,586,712

UNDERPINNING OF BUILDINGS Filed Aug. 5, 1947 2 $HEETS-SHEET 2 Inventor FORDHAT'] PRYKE a m M56410 Attorney Patented Feb. 19, 1952 PATENT OFFICE 1 2',5 a ,7r2 UNDERPlNNlNG 0F BUILDINGS Fordham Pryke, London, England Application A gses, 1947, Serial No. 766,364 In Great Britain August 29, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires August 2, 1965 This invention relates to the underpinning of 1" buildings, such. for example as may be required as: the result of the fracture of sinking of parts of thesubstructure thereof or for other reasons. Hitherto ithas been the practice with a building needing underpinning to provide elaborate shoring. structures for temporarily holding the remaining parts of the. building inplaceduring the repair work, and; then. completely to remove the parts of the walls orfoundations needing replacement and build them afresh, prior to the removal of. the temporaryshoring structures.

The. present invention has for its primary objeot :to provide a new structural element, 'by means. of which an improved method of under pinning can be carried outywh'ereby the" neces sityior the usual elaborate temporary shoring structures can inmostxcases be. eliminated altog'ether..

The structural elementraccording. to theinven tion comprises a channel-section block ofta-diequate thickness. through to take a heavy compressive stress, the two side limbs having fiat free ends which can engage with a flat surface over an extensive area, whilst the cross limb oi I the channel provides a fiat outer surface parallel to that of the free ends of the side limbs and is bored with a generally central vent holeof substantial size. The element, which is convenient- 1y made of reinforced concrete, may be of sub erate" loads, may comprise a fiat baseplate and. 1;

two 'or more of such channel-section blocks mounted one above another on the base plate,

each with itsfree ends resting on the flat surface 7 beneath it. Cine or more further flat plates'may be inserted between or on top of the blocks, if

desired.

An alternative form of pier for heavier loads may comprise a flat base plate, one channelsection block resting with its free ends on the base plate, a second channel-section block inverted on top of 'the'first (withor. without an intervening'flati plate or plates), and; a flattop plate resting: on the free ends of such second block.

In use: in a preferred underpinning arrange-' 7 Claims. (oi. 61-51) 55 taking moderate loads.

ment such piers are erected at spaced intervals beneath the wall to be supported, the hollow passages ;formed in the piers by the channel'grooves of the blocks all extending in the same direction H along the length of the wall to receive metal reinforcing rods which are finally embedded. in concrete to complete the underpinning structure.

In the preferred method of. underpinning according to the invention the supporting piers serve the double purpose of acting as shoring supports for the building during removal of the damaged parts to be replaced, and of forming an integral part of the final underpinning'structure.

A preferred underpinning arrangement accordingto the inventionv is illustrated by way of example in theaccompanying drawings, in which Figures 1 and 2 are central vertical sections at right angles to one another through a preferred oonstruction'of block.

Figure 3 i's-a perspective view of the block,

Figure 4 isa perspective view of anal; plate used'with the block,

Figuresfi-and 6' are :side views of two-alternative forms of supporting pier,

Figures 7 'and'B illustrate the preferred method of underpinning, Figure 3 being an enlarged perspective view showing the arrangement at a corner between two walls.

Figures 9' and, 10 are views similar toFigures B and 4. of an alternative form of block andrflat plate, and

Eigure 11 is aplanview of'the block of Figures. Theblock shown in Figures" 1-3 is of channelsection comprising two side; limbs A A connected by-a cross limb A at one end. The two-side limbs have flat-free ends lying parallel. to the outerisurface ofthe cross limb; the whole block being'externally of rectangular shape. .The cross limb A is centrally bored with. a vent-hole A 'of substantial size passing through from the fiat outersurfaceinto the channel. Theilimbszare of adequate thickness throughoutto take a heavy compressive stress- The two side limbs are bored with aligned-small holes A through which .a pin can be threaded to support reinforcing rods.

Figure 4' showsafiatplate B, of a size approximatelythe same as that of the hat outer surface oil thecross-limb- A1 of the block; the plate-being bored witha central vent hole B similar to'the vent hole. A in: the cross-limbo'fi the .block. One or. more :of such" plates are used with. the blocks toiiorm the "supportin'g'piers.

Figure 5 shows a supporting pier,suitable for This pier has two (or more) of the blocks of Figures 1-3 mounted on top of one another. with the free ends of the side limbs A of the upper block resting on the outer surface of the cross-limb A of the lower block. One of the flat plates B of Figure 4 is used as a base-plate for the free ends of the side limbs A of the lower block to rest on, and one or more others are placed on top of the upper block, as may be necessary to suit the height required. A further flat plate or plates may be interposed between the blocks, if desired. The blocks and plates are mortared together in the well-known bricklaying manner, as indicated at C.

Figure 6 shows an alternative, and preferred, form of pier for heavier loads. This arrangement differs from that.of Figure 5 in that the upper of the two channel-section blocks is inverted so that the free ends of its side limbs A point upwards. This figure also shows, by way of example, two of the fiat plates B of Figure 4 interposed between the two blocks.

Figure 6 serves also to show how the reinforcing rods fit through the blocks. In the example illustrated three rods D are. shown passing through the upper block and three more rods D through the lower block. The rods D through the upper block are supported by a pin E passing through the holes A in its side limbs and :a similar pin E in the lower block serves to hold the lower rods D down.

The piers shown in Figures 5 and 6 are suitable for supporting, say, a nine-inch wall, but for thicker walls, each pier may consist of two (or more) sets of blocks side by side, the flat plates in this case extending over the double set-of blocks, each plate being bored with two ".(or more) vent holes, one for each set of blocks.

The preferred method of underpinning according to the invention will now be described with reference to Figure 7. First of all a series of small portions at spaced intervals of the damaged substructure to be rebuilt are exposed and are removed one at a time, the amount removed being only sufficient to accommodate one supporting pier. Such pier is thereupon erected and completed, if necessary with one or more courses of bricks above the pier, so as to take its appropriate part of the load of the remainder of the building. The other exposed small portions of the substructure are then removed and replaced by supporting piers, until the set of piers is completed. This set of spaced piers constitutes a complete shoring structure for supporting the building during exposure and removal of the remainder of the substructure to be replaced. It should be mentioned "that the .piers are preferably built on the foundation of the original wall, since this will usually be stronger than the surrounding ground, but obviously the builder must be guided by his knowledge of thecause of the original damage in any particular instance.

Figure 7 illustrates a corner of a building in process of underpinning and shows a row of piers F F in front view along one wall and a side view of the end of the row of piers G along the other wall. These piers are of the kind shown in Figure 6, but without any flat plates between the upper and lower blocks. One course of bricks is; indicated at H on the top of each pier. The piers .in each row are arranged with the channel grooves in the blocks all facing in the same direction along the length of the wall to be supported.

When all the piers have been built to support the building, and the intervening parts of the substructure removed, the metal reinforcing rods D are threaded through the hollow passages in the piers along the lengths of the walls, some of the rods having hooked ends D to interlink with other rods, as indicated more clearly in the enlarged view of Figure 8, at the corners of the building and, if necessary, also at intermediate points in the walls. Metal loops, indicated at D,

may be placed around the reinforcing rods D at intervals between the piers, to strengthen the reinforcement still further.

The necessary framing for receiving the concrete is then set up, and it will often be convenient for the frame on the inner side to be built of brick to remain permanently in place, the outer frame usually being of wood, afterwards removed. The appropriate concrete mixture is then filled into the troughs so formed, and is pressed into the hollow passages in the piers from both sides. The vent holes A B in the cross-limbs of the blocks and the plates forming the piers serve to ensure that the passages become wholly filled without air pockets. The concrete is allowed to set, and the wood framing is removed, such brickwork. above the concrete substructure as may be necessary being re-erected to complete the underpinning. The piers F F G, which in their original hollow state formed the necessary shoring support for the building, are thus finally embedded in the concrete as an integral part of the final replaced substructure. Although the front faces of the blocks in the piers may form part of the final outer surface, it will usually be preferable for the framing'to be slightly spaced therefrom, so that the concrete is formed infront of the blocks as well, in order to give a continuous surface of concretein the finished structure, as indicated at J.

It will be appreciated that this method of un- (lei-pinning will usually render unnecessary the erection of elaborate shoring structures to hold the building in place during the work, and even when additional temporary shoring is necessary, such shoring can be of a much simpler nature than has hitherto been required.

It is not essential to the invention that the finished underpinning structure should be at or below ground level, and, if desired, the structure may be formed, in the manner above described, at 'a height'in a Wall well above ground level, the lower part of the wall then acting as the foundation on which the supporting piers are built prior to concreting. Part of such foundation may be cut away after the underpinning structure has been completed, if desired, for example to form.a doorway, the structure then constitutin the lintelto the door. Again, an underpinning structure, built at an appropriate height in a wall may be used to constitute an anchorage for tie rods for example for holding two opposite outside Walls of a building together.

Figures 9-11 show a modified form of the block and flat plate of Figures 1-4, wherein the side limbs A of the block are disposed in staggered relationship, so that the outer surface of the crosslimb A is of oblique parallelogram shape. This arrangement has the advantage of ensuring more reliably against air pockets in the concreting, but at the expense of some slight reduction of strength for the same thickness of concrete in the limbs of the block. The greater the degree of staggering of the sidelirnba. the. greater the safeguard against air pockets, but the greater also the reduction in strength, and generally it is preferable for the front end of one side limb to be more or less on a level with the rear end of the other side limb. The sharp edges of the block may be rounded or bevelled off, if desired, as indicated at A The plate B has the same parallelogram shape as the top surface of the block. In other respects the block and plate are similar to those above described.

It will be appreciated that the foregoing arrangement has been described by way of example only and may be modified in various ways within the scope of the invention. Thus it is not essential to the invention that the blocks should be made of reinforced concrete and other materials may be used, if desired, such as steel or other metal or plastics, having the necessary strength to provide the requisite shoring support prior to embedding in the final concrete substructure. Again it is not essential that the fiat plates used with the blocks should be of the same size as the blocks, and they may be smaller or larger, if preferred. 1

What I claim as my invention and desire to secure by Letters Patent is:

1. A method of underpinning buildings, according to which spaced small portions of a damaged substructure to be replaced are first removed, supporting piers having substantially horizontal passages running in the direction of the wall are then erected in the openings thus formed to act as shoring supports for the building, the remaining portions of the damaged substructure are then removed, metal reinforcing rods are then threaded through the hollow passages in the supporting piers, and the openings from which the remaining portions of the substructure were removed, the individual rods extending into at least a plurality of the piers, and the whole is then embedded in concrete to form the final beam-like underpinning structure, the supporting piers which originally acted as shoring supports during removal of the remaining portions of the damaged substructure thus forming an integral part of the final underpinning structure.

2. A method of underpinning buildings as claimed in claim 1, according to which each supporting pier is built up mainly of superimposed channel-section blocks, the channels of which form hollow passages for the reinforcing rods, each such block having two side limbs with flat coplanar free ends and a cross limb with a flat outer surface parallel to that of the free ends of the side limbs, such cross limb being bored with a generally central vent hole to aiford a venting connection between the hollow passages in the pier.

3. A method of underpinning buildings as claimed in claim 2, according to which each supporting pier is built up of a flat base plate, and a plurality of the channel section blocks mounted one above another on the base plate, the free ends of the side limbs of each block resting on the fiat surface beneath it.

4. A method of underpinning buildings as claimed in claim 3, according to which at least one flat plate is inserted between consecutive blocks in the pier, such plate being bored with a vent hole registering with the vent hole in the cross-limb of the block beneath it.

5. A method of underpinning buildings as claimed in claim 1, according to which each supporting pier is built up of a fiat base plate, a channel-section block having two side limbs with fiat coplanar free ends which rest on the base plate and a cross-limb with a flat outer surface parallel to that of the free ends of the side limbs such cross-limb being bored with a generally central vent hole, a second similar channelsection block inverted on top of the first with its vent hole registering with that of the first block and with its channel extending in a direction parallel both to that of the first block and to that of the building wall to be underpinned, and a fiat top plate resting on the free ends of the side limbs of the second block, the vent holes thus affording a venting connection between the channels which form the hollow passages for the reinforcing rods.

6. A method of underpinning buildings as claimed in claim 5, according to which at least one fiat plate is inserted between the two blocks, such plate being bored with a vent hole registering with those in the cross limbs of the blocks.

7. A method of underpinning buildings comprising the steps of removing spaced portions of the substructure thereof, erecting channeled supporting piers in the openings thus formed, removing the remaining portions of the original substructure, threading reinforcing rods through the channels in the supporting piers and the remaining open spaces, and filling the remaining open spaces resulting from removal of the original substructure, including the remainder of the channels in the piers, with concrete.

FORDHAM PRYKE.

REFERENCES CITED The following references are of record in the file of .this patent:

UNITED STATES PATENTS Number Name Date 563,130 Breuchard June 30, 1896 1,592,476 Torrecelli July 13, 1926 1,600,895 Larry Sept. 21, 1926 1,662,727 Wait Mar. 13, 1928 2,298,184 Von Rosenberg Oct. 6, 1942 2,320,690 Willis June 1, 1943 FOREIGN PATENTS Number Country Date 775,499 France 1934 

